In situ imaging of ground granulated blast furnace slag hydration

Abstract

Ground granulated blast furnace slag (GGBFS) reacts with water in the presence of calcium sulfates and alkalis and is frequently used as a partial replacement for portland cement in concrete. The hydration products are known to be slightly different compositionally and morphologically than those of pure portland cement hydration. In this study, a new technique, soft X-ray transmission microscopy, was used to image the hydration of slag in a variety of solutions to investigate the effects of alkali sulfate and hydroxide activators on the morphology of the resulting hydration products. This microscopy method is unique in that it enables high resolution in situ observation and documentation of the formation of hydration products over time in wet samples at atmospheric pressure.

Keywords

Gypsum Portland Cement Calcium Hydroxide Ettringite Hydration Product

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Notes

Acknowledgements

The authors would like to thank Lafarge Central Research, France, for supporting this work. Research at XM-1 is supported by the United States Department of Energy, Office of Basic Energy Sciences under contract DE-AC 03-76F00098. The authors also gratefully acknowledge the help of G.P. Denbeaux, A.L. Pearson, D.A. Silva, and J.S. Swinnea with the experiments described herein.